A High-Efficiency Wavelength-Tunable Monolayer LED with Hybrid Continuous-Pulsed Injection

Yi Zhu; Bowen Wang; Ziyuan Li; Jian Zhang; Yilin Tang; Juan F Torres; Wojciech Lipiński; Lan Fu; Yuerui Lu

doi:10.1002/adma.202101375

A High-Efficiency Wavelength-Tunable Monolayer LED with Hybrid Continuous-Pulsed Injection

Adv Mater. 2021 Jul;33(29):e2101375. doi: 10.1002/adma.202101375. Epub 2021 Jun 6.

Authors

Yi Zhu^{1

2}, Bowen Wang¹, Ziyuan Li², Jian Zhang¹, Yilin Tang¹, Juan F Torres¹, Wojciech Lipiński¹, Lan Fu^{2

3}, Yuerui Lu^{1

4}

Affiliations

¹ Research School of Electrical, Energy and Materials Engineering, College of Engineering and Computer Science, the Australian National University, Canberra, ACT, 2601, Australia.
² Department of Electronic Materials Engineering, Research School of Physics and Engineering, the Australian National University, Canberra, ACT, 2601, Australia.
³ Australian Research Council Centre of Excellence for Transformative Meta-Optical Systems, Research School of Physics, the Australian National University, Canberra, ACT, 2601, Australia.
⁴ Australian Research Council Centre of Excellence for Quantum Computation and Communication Technology, the Australian National University, Canberra, ACT, 2601, Australia.

PMID: 34096112
DOI: 10.1002/adma.202101375

Abstract

High-efficiency and wavelength-tunable light-emitting diode (LED) devices will play an important role in future advanced optoelectronic systems. Traditional semiconductor LED devices typically have a fixed emission wavelength that is determined by the energy of the emission states. Here, a novel high-efficiency and wavelength-tunable monolayer WS₂ LED device, which operates in the hybrid mode of continuous-pulsed injection, is developed. This hybrid injection enables highly enhanced emission efficiency (>20 times) and effective size of emission area (>5 times) at room temperature. The emission wavelength of the WS₂ monolayer LED device can be tuned over more than 40 nm by driving AC voltages, from exciton emission to trion emission, and further to defect emission. The quantum efficiency of defect electroluminescence (EL) emission is measured to be more than 24.5 times larger than that from free exciton and trion EL emission. The separate carrier injection in the LED also demonstrates advantages in allowing defect species to be visualized and distinguished in real space. Those defects are assigned to be negatively charged defects. The results open a new route to develop high-performance and wavelength-tunable LED devices for future advanced optoelectronic applications.

Keywords: 2D materials; WS 2; hybrid injection; light-emitting diodes; wavelength-tunability.

Abstract

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